Rare earth elements (REEs) are used in many household and industrial materials. For example, rare earth elements are used in phosphor powders of fluorescent lighting and light emitting diodes (LEDs), catalysts, magnets, electronic devices including computer memory, DVDs, illuminated screens of electronic devices (e.g., cathode ray tubes, plasma displays, etc.), rechargeable batteries, cellular phones, or other materials.
Unfortunately, the global supply of rare earth elements is limited. One potential source of rare earth elements is in recycled used devices and materials incorporating the rare earth elements, such as from used electronics, used rare earth magnets, or used phosphor fluorescent lamps.
Recycling of rare earth elements from used fluorescent lamps and other materials has presented technical and practical challenges. For example, rare earth-containing materials, such as lighting phosphors, often contain mercury, which may exist in several chemical forms. In addition, the rare earth elements used in the many materials are relatively inert and are conventionally present only in low concentrations. Further, the various rare earth elements contained in combination in the many materials exhibit relatively similar chemistries and are, therefore, difficult to isolate from each other. Because of the aforementioned and other difficulties associated with recovering substantially pure rare earth elements from used materials, recycling of rare earth elements from such materials has been both unsuccessful and uneconomical in the past.